Current mapping for reported tornadoes on the ground and warning conditions
Jeff Master's Weather Blog tends to have the most current and accurate information which can be useful for planning trips in areas expected to be hit by severe weather. And here's a general post about whether or not tornadoes in the USA are getting stronger by year. The short answer? The data is not clear...
And to get an idea of what these super-storms can do... Click on this link and then grab the blue slider bar and move left to right to see what the before and after was on this neighborhood!